Truing mechanism



2 Sheets-Sheet 1 Nov. 10, 1942. E. F. RENDER TRUING MECHANISM Filed Sept. 11, 1941 h N v N SN 4 h o v Q WTQ .n

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Nov. 10, 1942. E. F. RENDER TRUING MECHANISM Filed Sept. 11, 194i 2 Sheets-Sheet 2 INVENTOR. ZiA/fiflfPf/YMP BY Wm ATTORNEY Patented Nov. 10, 1942 TRUING MECHANISM Elijah F. Render, Deer Park, Ohio, assignor to Cincinnati Grinders Incorporated, Cincinnati, Ohio, a corporation of Ohio Application September 11, 1941, Serial No. 410,449

4 Claims.

This invention relates to truing mechanisms for grinding machines and the like.

One of the objects of this invention is to prvide an improved mechanismfor truing the grinding wheels of a duplex grinding machine with a single truing tool.

Another object of this invention is to provide a truing mechanism having quick adjusting means for size changing purposes whereby successive grinding wheels may be trued to different diameters in a single stroke of the truing tool.

A further object of this invention is to provide an improved truing mechanism which is quickly adjustable for truing different compound surfaces on the several grinding wheels of a duplex grinding machine.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification, considered in conjunction with the accompanying drawings forming a part thereof and it is to be understood that any modifications may be made in the exact structural details there shown and described, within the scope of the appended claims, without departing from or exceeding the spirit of the invention.

Referring to the drawings in which like reference numerals indicate like or similar parts:

Figure 1 is a plan view of a duplex grinding machine showing the application of this invention.

Figure 2 is an enlarged plan view partly in section of the truing mechanism.

Figure 3 is a vertical section on the line 33 of Figure 2.

In the production manufacture of small parts having two surfaces to be ground it is sometimes the practice to mount two grinding wheels on the same spindle of a plain grinding machine and in such properly spaced relation thereon that by the use of an infeed grinding cycle the two surfaces may be ground simultaneously. Where the surfaces are of different diameters it will be obvious that the grinding wheels must be trued to different diameters and that the differential between these trued diameters must be equal to a high degree of precision to the differential between the desired finish diameters of the work because no relative adjustment can be made between the wheels to correct one work diameter with respect to the other.

In Figure 1 of the drawings there is shown a plain grinding machine which may be of the type shown in United States Patent No. 2,101,644,

issued December 7, 1937, to the spindle of which has been applied a pair of grinding wheels indicated by the reference numerals It] and It thus making the machine a duplex grinding machine.

A work piece, indicated generally by the reference numeral I2, has two surfaces It and M which are to be ground to different diameters by the infeed grinding method. The surfaces l3 and M are cylindrical throughout the major portion of their length but the surface 13 terminates in a fillet [5, while the surface [4 terminates in a fillet l6, and the radii of these fillets are different whereby it should be evident that the entire success of the grinding operation depends upon the accuracy to which the grinding wheels are trued individually and with respect to each other.

It may be well to point out at this time that a. grinding machine built in accordance with the patent supra is provided with certain controls, the hand wheel I! being manually rotatable to effect longitudinal movement of the table 18 upon which are mounted the head and tailstocks l9 and 20 respectively for supporting the work piece forvrotation; the infeed control wheel 2| which controls movement of the saddle indicated by the reference numeral 22 upon its guideways 23 whereby the table and work mounted thereon may be moved toward or from the grinding wheel; the start and stop control lever'22 for initiating power reciprocation of the table; and the table reversal control 23 which may be manuaily operated by the handle 24 or automatically operated by dogs on the table engaging the Wings 2%) and 26 of control 23'.

Reference may also be had to the patent for the manner in which these controls are operatively connected to the operating mechanism of the machine for effecting the Vfi.ilUl.lS results enumerated in connection with each.

The truing mechanism constituting this invention is so designed and constructed that it may be permanently applied to the table of the machine as shown in Figure 1, whereby no time need be lost in mounting replaceable devices. Again, it is mounted on the end of the table where it does not interfere with the working area of the machine which must necessarily be clear for quick loading and unloading purposes.

More specifically, the truing mechanism comprises a base plate 27 as shown in Figure 3 which is secured directly upon the table 18 and a sub-support 28 upon which is formed a circular guideway 2% having a beveled guide surface 36 and a vertical guide surface 3!.

The axis of curvature 32 of the circular guideway lies outside of the fixture as indicated in Figure 3, and beyond the truing point 33 of the truing tool 3%. The truing tool support 35 is mounted on this guideway and is provided with a beveled surface 35 which is circular in extent for engagement with the guide surface 3t.

These parts are held in engagement by a gib 31 which is held in engagement with the surface Si by set screws such a It is the adjustment of these screws which determines the tightness or looseness of the fit between the opposing guide surfaces. When the proper fit has been obtained a lock nut 39 threaded on the adjusting screw is tightened. The truing tool support 35 also rests upon the flat surfaces it and ti on the sub-support and is held against lifting by the interengaging beveled surfaces 38 and St and the gib 42 which is secured to the underside of the support 35 as by bolts 43 and thus in engagement With the guide surface id formed on the underside of the support 28.

Oscillating movement of the support 35 about its axis of rotation 32 is effected by a worm and worm gear comprising a worm M which is fixed with a shaft 45, and worm wheel teeth it which are out directly in the support 35 and integral therewith. The shaft a is supported by bearing blocks G6 and t? more particularly shown in Figure 2 which are secured to the base 2'5 by screws 48. A hand wheel 39 is secured to the end of the shaft for effecting manual rotation thereof.

The truing tool St is secured in a socket 69 by a set screw 58 of a shiftable plunger 5i. A spring 52 is interposed between a shoulder 53 on the plunger and a shoulder at on the support- 35 for continuously urging the plunger in a direc tion away from the grinding whee-l. The plunger may be moved manually by a handle 55 which is screwed into the plunger, the plunger passing through an elongated slot 55 formed in the support for this purpose. The rear end of the plunger is provided with a follower 57 which is adapted to engage any one of three annular stop discs or cams 58, 59 or 6% which are integrally secured to a shiftable support St. The support has an elongated journal 62 which rides in a bearing 63 formed in the support 35, and is guided at the other end in a bearing A control knob 65 is utilized for shifting the support to any one of three positions to align any one of the three stop members 58, 5% r Gil with the follower 57. To assist in positioning the support it is provided with a series of properly spaced V- notches 66 which are engageable by a spring pressed ball 6'! to hold it in any one of its, three positions.

To guide the operator in using the mechanism and to indicate when the axis of the plunger Si is perpendicular to the axis of the grindin wheels the support 35 is provided with a laterally extending pin 68 which is engageable with a, stop pin 69 carried by the fixed support 2i and this serves to limit the counterclockwise rotation of the truing tool support and to align it perpendicular to the axis of the grinding wheels.

In the operation of the device the saddle is retracted and the table shifted to the left as viewed in Figure 1 until the truing tool is to the left of the grinding wheel H3. With the follower 5? in engagement with the stop 58 the saddle is adjusted until the truing tool is in alignment with the face of the wheel whereby the table may be traversed toward the right to true the cylindrical surface it shown in Figure 2 of the wheel 83. As previously mentioned, there is a dinerence in diameter between the grindingwheels and in the case illustrated the grinding wheel It! is smaller in diameter than the grinding wheel ll. The stop 59 is, therefore, made smaller in diameter than the stop 58 so that the differential in the diameters of the stops is equal to the differential desired between the diameters of the grinding wheels.

The table may be traversed by power to true the wheel l '2 through operation of the control 22', or it may be shifted by hand through operation of the hand wheel H. In any case, as soon as the truing tool passes out of engagement with the wheel iii, the plunger 5! is shifted slightly to take the pressure off of the stop 5% and the stop support 6! shifted one station so that upon release of the handle the follower will engage the stop 5%! to position the truing tool to true the diameter of wheel H in proper differential relation to the diameter of the wheel i8. With a reasonable rate of power feed this adjustment be made quickly and the parts properly adjusted to their new position before the truing tool reaches the grinding wheel i Thus, the mechanism serves as a quick adjusting mechanism for changing the truing radius of the truing tool.

If it is necessary to make more than one pass of the diamond across the faces of the wheels the table may be reversed and the saddle support adjusted micrometrically by the wheel 2! which is equipped to make such adjustment and after the tool passes out of engagement with the wheel II it may be quickly adjusted and positioned by the stop 58 by the time the truing tool reaches the grinding wheel Hi. Thus, two different diameters may be trued with the same ease and quickness that a single diameter is trued.

As previously mentioned, the work piece has two fillets l5 and it which are of different radius. The grinding wheel I i must, therefore, be provided with a curved surface '1! for grinding the fillet iii and the grinding wheel iii must be provided with a curved surface 12 for grinding the fillet it. These fillets being of different diameter they cannot be trued with the same setup but the mechanism of this invention provides means whereby quick adjustment may be made for accommodating both radii. It is accomplished in this manner. When the follower 51 is in engagement with the stop 58 the point of the truing tool is spaced from the axis of rotation 32 of the fixture a distance equal to the radius of the surface 12.

Therefore, when the follower 5? is in engagement with the stop 58, th fixture maybe rotated by means of the hand wheel 58 to obtain the radius '52. In other words, the same step can be used for straight truing and for truing one radius of one of the grinding wheels because for straight truing it is immaterial what the spacing is between the diamond point and the axis of rotation of the truing tool support.

To form the radius H the additional stopfifl is provided and this is made smaller than the stop 58 by an amount equal to the difference between the radius of the surface l! and the radius of the surface 72.

It is, of course, desirable that the straight and curved surfaces of the wheel be trued in one continuous stroke of the truing tool so that on lines are left on the wheel to mar the finished surface of the work. This is accomplished in connection with. the wheel H by setting the follower in contact with the stop 60 and relatively shifting the parts to position the truing tool in line with the right hand face of the wheel H and then relatively adjusting the supports by the hand wheel 2| until the truing tool is just barely in contact with the face of the wheel. The table is then traversed by hand through manual rotation of the hand wheel I1, and at the point of tangency between the curve and straight surfaces rotation of the hand wheel I! is stopped and rotation of the hand wheel 59 begun, in such manner that no stoppage in the movement of the truing tool occurs whereby the straight and curved surfaces will be trued in one continuous movement of the truing tool.

In order to indicate to the operator where this point of tangency occurs as indicator plate 13 is attached to the sub-support 28, as shown in Figure 2, by means of clamping bolts 14 which pass through elongated slots 15 in the plate 13. This plate is provided with two marks 16 and H which cooperate with a pointer l'B which is fixed to the saddle 22. As the table is traversed by the hand wheel ll the mark 11 will approach the pointer I8 and the operator effects the changeover when the pointer and the mark are in alignment.

After the wheel I I has been trued the operator shifts the follower 51 into engagement with the stop 58 and aligns the truing point with the right hand face of wheel It and repeats the operation of traversing the table by the hand wheel I! but this time the changeover is effected when the pointer 18 is in alignment with the mark 16.

Since the grinding wheels and II are dished wheels as shown in Figure 2 the point of tangency between the curved surfaces and the straight surfaces will gradually shift toward the right as the wheels wear down. In order to compensate for this the plate 13 is provided with the elongated slots whereby the plate may be gradually shifted toward the right and reclamped at various times through the life of the wheels. After the wheel III has been trued by continuous movement of the truing tool in a left hand direction across the face of the wheel, the operation may be reversed by effecting the rotation first and the longitudinal movement second in a continuous manner and then after passing out of engagement with the wheel ID the truing tool may be reset in engagement with the stop 59 and traversed once across the straight portion of the wheel H to insure that the diameters of the wheels are in proper relation. This may be done without leaving any lines on the wheel H and insures that the cylindrical surfaces on the work which are the important surfaces are produced with the desired precision relationship.

There has thus been produced a very simple and compact truing mechanism which will per form varied and complicated truing operations in an eificient manner and which any normally skilled operator will not experience difficulty in learing to operate.

What is claimed is:

1. A truing device for application to a grinding machine having a base portion adapted to be secured to the table of the machine, said base having an upstanding arcuate guide portion, a second support member mounted on the first having arcuate ways intervening with the guide portion of the first support whereby the parts are connected for relative oscillatory movement, said supplemental support having passages formed therein angularly related with respect to each other, a truing tool'holder slidably mounted in one of said passages, a control shaft slidably mounted in the other of said passages, a plurality of stop means mounted on said control shaft, an abutment onrthe tool holder projectable in the direction of the shaft for engagement with a stop element. thereon, and means for variably securing the shaft in selectively adjusted positions whereby to align different of the stop means thereon with the abutment on the tool holder, substantially as and for the purpose described.

2. A truing device for application to a grinding machine having a base portion adapted to be secured to the table of the machine, said base having an upstanding arcuate guide portion, a second support member mounted on the first having arcuate'ways intervening with the guide portion of the first support whereby the parts are connected for relative oscillatory movement, said supplemental support having passages formed therein angularly related with respect to each other, a truing tool holder slidably mounted in one of said passages, a control shaft slidably mounted in the other of said passages, a plurality of stop means mounted on said control shaft, an abutment on the tool holder projectable in the direction of the shaft for engagement with a stop element thereon, means for variably securing the shaft in selectively adjusted positions whereby to align different of the stop means thereon with the abutment on the tool holder, and means for continuously urging the tool holder into retracted position to maintain the abutment in engagement with a selected stop means.

3. A truing device for application to a grinding machine having a base portion adapted to be secured to the table of the machine, said base having an upstanding arcuate guide portion, a second support member mounted on the first having arcuate ways intervening with the guide portion of the first support whereby the parts are connected for relative oscillatory movement, said supplemental support having passages formed therein angularly related with respect to each other, a truing tool holder slidably mounted in one of said passages, a control shaft slidably mounted in the other of said passages, a plurality of stop means mounted on said control shaft, an abutment on the tool holder projectable in the direction of the shaft for engagement with a stop element thereon, means for variably securing the shaft in selectively adjusted positions whereby to align different of the stop means thereon with the abutment on the tool holder, means for continuously urging the tool holder into retracted position to maintain the abutment in engagement with a selected stop means, the supplemental support having a slot formed therein communicating with the tool holder receiving passage, and actuating means exteriorly disposed as respects the supplemental support engaging the tool holder by way of the slot whereby the interengagement of said means with the sides of the slot secures the tool holder against rotative movement while the projecting portion is actuable for projection of the tool holder in a direction away from the stop means.

4. A truing mechanism for application to a grinding machine table or the like including a base element securable to the table, said base having an upstanding arcuate portion providing a segmental guideway, a supplemental support portion mounted on the base portion having interfitting engagement with the segmental way on the base, said supplemental support having a worm rack formed thereon adjacent the away, bracket portions rising from the base, a shaft iournaled in said bracket portions having a .central worm meshing with the worm rack on the supplemental support whereby the worm normally locks the supplemental support against angular movement relative to the base but may be rotated to effect such movement of the parts, said supplemental support having a transverse guide passage formed therein extending in a radial direction as respects the ,arcuate path, a iruing tool holder slidably mounted Within said passage, means for urging said tool holder in a circumferentially outward direction, said supplemental support ;having transverse bearing passages formed therein lying in substantially .a common plane with the axis of the tool holder passage, a shaft journaled in said bearing passages and having .a portion in intersecting relation with the outward potential path of movement of the tool, a multiple number of different dimension stop elements carried by the shaft and selectively positionable in alignment with the tool variably to limit the outward movement thereof for determination of the position of the tool during rectilinear movement of the device and of the radius of arc generatable by the tool on arcuate movement of the supplemental support, means for shifting the tool support in a direction away from the shaft to facilitate shifting of the shaft and stop elements carried thereby, and means for variably positioning the shaft selectively to align individual stop elements with the tool holder substantially as and for the purpose described.

ELIJAH F. RENDER. 

